"Guess the glory days of Facebook are over", I don't agree at all. In Fact, they are just starting making money. As more and more people use fb across the world, they ad campaign will grow accordingly.
This is just small setback for such a Giant platform and I am sure it will grow. Good thing for facebook is it has 0 competition just like Google in the search engine. It has become so big that it will enormous amount of competition to turn.